Fender for large ship

ABSTRACT

In a rectangular tubular fender for large ship, made of elastic material and composed of a buffer, a fixture and two supports provided between said buffer and said fixture, the present invention contemplates an improvement therein wherein the exterior surfaces of said supports being made parallel to each other, the interior surfaces of said supports being flat and parallel to said exterior surfaces in the middle portion, the adjacent parts of said middle portion to said buffer and said fixture being curved, and the junctions between said curved portion and said buffer or fixture being depressed with a notch.

[22] Filed:

Narabu Sept. 12, 1972 [54] FENDER FOR LARGE SHIP [72] Inventor: JiroNarabu,Tokyo,Japan [73] Assignee: Seibu Gomukogaku Kogyo Kabru- V .shikiKe sha, 0 51 9?! pan Sept. 14, 1970 21 Appl. No.: 71,722

Primary Examiner-Milton Buchler Assistant Examiner-Gregory W. OConnorAttorney-George B. Oujevolk [57] ABSTRACT In a rectangular tubularfender for large ship, made of elastic material and composed of abuffer, a fixture and two supports provided between said buffer and saidfixture, the present invention contemplates an improvement thereinwherein the exterior surfaces of said supports being made parallel toeach other, the interior surfaces of said supports being flat andparallel to said exterior surfaces in the middle portion, the adjacentparts of said middle portion to said buffer and said fixture beingcurved, and the junctions between said curved portion and said buffer orfixture being depressed with a notch.

1 Claim, 8 Drawing Figures [52] U.S. Cl ..ll4/2l9 [51] Int. Cl. ..B63b21/00 [58] Field ofSearch ..l14/2l9 [56] References Cited UNITED STATESPATENTS 3,507,123 4/1970 Miura ..l14/219 3,533,242 10/1970 Narabu, ..11.4/219 X 3,418,815 12/1968 Kurnazawa ..1 14/219 X mmrmsirlzmz 3.690.280

SHEET 2 [1F 2 FIG. 5 FIG. 4

2 L/m'a Mmly INVEA TOR.

FENDER FOR LARGE SHIP BACKGROUND OF THE INVENTION The present inventionrelates to a fender to be fitted to quays, etc., for cushioning a largeship.

BRIEF DESCRIPTION OF THE PRIOR ART SUMMARY OF THE INVENTION Theobjective of the present invention is to offer a fender with greatenergy absorption inwhich only the displacement increases, without thereaction being increased under shock; Broadly stated, in a rectangulartubular fender for a large ship, made of elastic material and composedof a buffer, a fixture, and two supports provided between said' bufferand said fixture, the present invention contemplates an improvementtherein wherein the exterior surfaces of said supports being madeparallel to each other, the interior surfaces of said supports beingflat and parallel to said. exterior surfaces in the middle portion, theadjacentparts of said middle portion to said buffer and said fixture iscurved, and the junctions between said curved portion and said buffer orfixture being depressed with a notch. Other objectives of this inventionwill be apparent by reading the description of the following embodimentwith reference to the accompanying drawings.

DETAILED DESCRIPTION FIG. 1 is a perspective end view of the fendercontemplated herein;

FIG. 2 is a view along lines 11-11 of FIG. 1;

FIG. 3 shows one type of tubular cross-section of the prior art;

FIG. 4 illustrates another type of tubular cross-section of the priorart;

FIG. 5 graphically shows the. characteristics of the tubularcross-sections shown in FIGS. 3 and 4;

FIG. 6 is a modification of the tubular cross-section shown in FIG. 4;

FIG. 7 is a further modification of the tubular crosssection shown inFIG. 4; and,

FIG. 8 again graphically shows the characteristics of the tubularcross-sections shown in FIG. 6 and FIG. 7.

FIGS. 1 and 2 illustrate a fender made in accordance with thisinvention. This fender represents a hollow cylinder with rectangularcross-section. This cylindrical body is made of an elastic material likerubber, and it consists of a buffer 1 which comes into contact with theship side; a fixture 2 which contacts the quay wall and runs parallel tosaid buffer; and two supports 3 which are inserted between said buffer 1and said fixture 2 and are flat on the outside surface, these two flatsurfaces being parallelto each other. Said buffer 1 and said fixture 2have embedded reinforcing plates 4, 5.

Holes 6 bored on the surface of said buffer are intended for attachmentof another buffer, while holes 7 bored on the surface of said fixtureare intended for attachment of the fender to the quay wall, etc.

Interior surfaces of said supports 3 have their middle portion 3a flatand parallel to the exterior surface; the adjacent portions 3b of saidmiddle portion 3a to the buffer and to the fixture are curved; and thejunctions between said curved portions 3b and the buffer and fixture aredepressed with a notch.

The fender according to this invention is designed as a rectangular tubefor the purpose of enlarging the contact area with the ship and reducingthe reaction per unit area. Its sectional profile is dictated by thepressure-receiving area and its internal shape is selected to make thereaction small and the displacement large. Tubular fenders withcross-sections, as illustrated in FIGS. 3 and 4, have been publiclyknown. One illustrated in FIG. 3 shows a characteristic curve, like 0-curve in FIG. 5, while one illustrated in FIG. 4 does a characteristiccurve, like the P-curve of FIG. 5. In these fenders, however, thereaction rise is sharp and the energy absorption is extremely poor.

The fender of FIG. 4 has two supports parallel to each other and thepresent inventor tried ,to improve this fender. As shown in FIG. 6,leaving the flat portion 3a of the support as it is and providing acurved portion 3b between the buffer and the fixture, he obtained acharacteristic curve, like the R- curve in FIG. 8. When,

I with the thickness of support kept constant, the radius of curvedsurface was increased and the fiat portion 3a was reduced, however, thedisplacement of support did not increase and the rise of thecharacteristic curve became steep. Conversely, when the radius wasreduced and the flat portion 3a was enlarged, the reaction dropped, butthe rise of the characteristic curve remained relatively steep.

By providing a notched depression 3c, as shown in Fig. 7, between thecurved part and the buffer and fixture, only the displacement could bemade as large as about 50 percent, as given by the S-curve in FIG. 8.

As testified by various experiments, the recommendable H(height) vs.W(width) relation is 2H i W R 1.25H. The desirable thickness (2) of thesupport, depending on the mutual relation between the radius (R) ofcurved surface, the length (E) of the fiat portion (3a) and the distance(M) of the notched depression from the outside surface of support, ist=(0.20 0.26)-H. The desirable range of E is E=(0.3 0.4)H, that of Rbeing R=(0.22 0.30)H and that of M being M=.0.265-

A fender meeting these conditions has, as indicated in FIG. 8, a lowreaction, a large displacement and a great absorption energy (A).

The fixture in this example represents a flat plate, but it may beseparated by an open groove cutin the middle.

What is claimed is:

1. In a rectangular tubular fender to be fitted to quays for docking alarge ship, made of elastic material and composed of a buffer (1), afixture (2) and two supports (3) provided between said buffer and saidfixture, the improvement therein wherein the exterior surfaces of saidsupports are made parallel to each other, the interior surfaces of saidsupports being flat and parallel to said exterior surfaces in the middleportion (3a) the adjacent parts (3b) of said middle portion to saidbuffer and said fixture being curved, and'the junctions (30) betweensaid curved portion and said buffer or fixture being depressed with anotch, said fender meeting the following conditions:

1. In a rectangular tubular fender to be fitted to quays for docking alarge ship, made of elastic material and composed of a buffer (1), afixture (2) and two supports (3) provided between said buffer and saidfixture, the improvement therein wherein the exterior surfaces of saidsupports are made parallel to each other, the interior surfaces of saidsupports being flat and parallel to said exterior surfaces in the middleportion (3a) , the adjacent parts (3b) of said middle portion to saidbuffer and said fixture being curved, and the junctions (3c) betweensaid curved portion and said buffer or fixture being depressed with anotch, said fender meeting the following conditions: 2H > OR = W > OR =1.25H, t (0.20-0.26)H, E (0.3-0.4)H, R (0.22-0.30)H, M 0.265.H + OR -10%, where H is the height, W is the width, t is the thickness of themiddle portion of the support, E is the length of flat portion of thesupport, R is the radius of the curved surface, and M is the distance ofnotched depression from the exterior surface of the support.